Abstract:
Demand for low weight to strength ratio for exclusive application in automobile and aerospace components
created scope for advance studies on Metal Matrix Composites (MMCs). However, machining of MMCs
challenges for conventional machining processes due to uneven hardness, matrix of composites and
undesired tool life. Electric Discharge Machining (EDM) is one of the unconventional material removal
process, which offers alternatives for machining of MMCs because, being a non-contact process it can be
machine excessive harder material, intricate shape with better surface finish and tool life. The evolved heat
during EDM process and subsequent flushing of machined debris and rapidly resolidified layer is formed
by the re-solidification of residual molten material on the machined surface during the EDM process leaves
behind recast layers which is extremely hard and brittle. In the presents study optimization of process
parameters to minimize the surface roughness of the rapidly resolidified layer of Al 7075 MMC while
machining using EDM process is carried out using the Taguchi tequniues. The gap current, pulse on-time
and pulse off-time were considered as process parameters. The formation of resolidified layers is
investigated in terms of the surface roughness as response variables inside the hole and near the hole while
EDM drilling.